Liquid rheostat



Feb. 17. 1925.

c. c. WHITTAKER LIQUID RHEosTAT giled oct. 18, 1929 AToRNEY Feb. 17.1925.

C. C. WHITTAKER LIQUID RHEosTAT Filed oct.l 18

Feb. 17. Y1925.

C. C. WHITTAKER 4 Sheets-Sheet 5 Filed Oct. v18, 1920 INVENTOR22424/9556 ffii/2f BY M ATTORNEY WITNESSES:

Feb. 17. 1925. 1,526,404

c. c. WHITTAKER LIQUID RHEOSTAT Filed Oct. 18, 1920 4 Sheets-Sheet 4 r uI R WITNEssEs: 7. 'f. Q INVENTO .J5/.MW

Charlas C. Wizz'akcr BY TTRNEY Patented Feb. 17, 1925.

UNITED STATES 1,526,404 PATENT OFFICE.

CHARLES C. WHITTAKER, OIE PITTSBURGH, PENNSYLVANIA, ASSIGNOR- TOWEST'ING- HOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OFPENNSYL- VANIA.

LIQUID R-HEOSTAT.

Application filed October 18, 1920. Serial No. 417,533.

To all whom it may concern.'

Be it known that I, CHARLES C. lVHiT- Tanna, a citizen ot the UnitedStates, and a resident of Pittsburgh, in the county otl Allegheny andState of Pennsylvania, have invented a new and useful Improvement inLiquid Rheostats, of which the following is a specification.

My invention relates to liquid rheostats and it has particular relationto liquid rheostats employed in motor-control systems that are traversedby relatively large currents, such, for example, as those employed inelectric locomotives.

One object of my invention is to provide means for regulating thequantity of electrolyte in a liquid rheostat and for readily dischargingelectrolyte from the rheostat.

Another object of my invention is to provide improved barriers betweenthe electrodes of a liquid rheostat, whereby the distance traveled bythe current in passing from one electrode to another is decreased as thedepth of electrolyte surrounding said electrodes is increased.

Another object ot my invention is to provide means for preventing lossof electrolyte because of leakage of the rheostat.

Still another object of my invention is to provide an arrangement otelectrodes whereby their connection through the electrolyte is graduallychanged from delta to star connection upon the gradual increase of thequantity of electrolyte in said rheostat.

A further object of my invention is tol provide an improved electrodehaving relatively greater strength than prior electrodes ofsubstantially the same weight and size and which will effect a moregradual change in resistance upon being immersed in electrolyte.

For a better understanding of my invention, reference should be made tothe accompanying drawings- Figure 1 of which is a view, partly inelevation and partly in section, ot a liquid rheostat designed inaccordance with my invention and positioned in an electric locomotive.

Fig. 2 is a view, partly in section and partly in elevation, ot therheostat shown in Fig. 1, taken parallel to the side of the rheostatwhich is shown in Fig. 1.

Fig. 3 is a view, partly in elevation and partly in section, of theliquid rheostat shown in Fig. 1, taken perpendicularly to the side ofthe rheostat which is shown in Fig. 1.

Figs. t and 5 are views, partly in section and partly in elevation, of aweir, comprising a plurality of pivotally mounted shutters, which are apart of the liquid rheostat shown in Fig. 1.

Fig. G is a view, partly in plan elevation, and partly in section, ofthe rheostat shown in Fig. 1.

Figs. 7 and 8 are views, in side and end elevation, respectively, of abarrier employed in the liquid rheostat shown in Fig. 1.

Fig. 9 is a view in side elevation of a barrier employed in the liquidrheostat shown in Fig. 1.

Figs. 10 and 11 are views, in side and end elevations, respectively, ofan auxiliary electrode employed in the liquid rheostat shown in Fig. 1.

Referring particularly to Fig. 1, an electric locomotive 1 having sides2, a floor 3, and a roof 4, has a liquid rheostat 5 mounted therein. Theliquid rheostat 5 is superimposed upon an electrolyte tank 6 and islocated adjacent to a cooling tower 7, which is superimposed upon awater tank 8.

A motor 9 operates a pump 10 to force electrolyte from a pipe 12, whichleads from the electrolyte tank 6, into pipes 13 and 14. The pipe 13conducts electrolyte from the pump 10 into the liquid rheostat 5. rThepipe 1t conducts a portion ot the electrolyte from the pump 1 to thecooling tower 7.

The cooling tower 7 comprises a coil 15, which is showndiagrammatically, through which heated electrolyte is circulated.

The pipe 16 conducts water from the water tank into the cooling tower 7,when it becomes necessary to decrease the density of the electrolyte inthe reservoir 6. A funnel 17 from the liquid rheostat conducts thevaporized water of the heated electrolyte from the liquid rheostat tothe exterior ot the locomotive 1.

Referring to Fig. 2, two communicating compartments in side-by-siderelation hare a plurality of main electrodes 18 mounted therein andseverally positioned between soapstone barriers 19. The main electrodes18 are :so constructed that their cross-sections resemble the 'letter Y,the-upper legs 'o the Y being bent parallel to the lower leg of the Y.Auxiliary electrodes 21 are positioned within theloops formed =by theyupper legs of the electrodes 18 Aby means of hori`- Zontal bolts 22 andspacing members 23 mounted thereon.

Insulators 24 are Vprovided to insulate bolts 25, by means of which theelectrodes 1 8 are,mounted, from the .top V: mem'bers *25a of:the'liquid vrheostat 5. plurality Off electrodes 26 are suit-ablyvmounted upon the top .member a, -as later described, `and areelectrically connected thereby to each other and to end plates 27 ofythe liquid rheo's'tat 5. The auxiliary electrodes 21 are 'connectedelectrically fto the end plates 27 by bolts 22.

The top memlber or coyer125a is braced by angles 29= to prevent-Vertical distortion by vreasonofthe weight offelectrodesv 158, 21 andby `means of an arm 41 and afbolt42.

Eachgrod 'or arm38 `hasa bent portion 43 at its upper end. T he portion:43 .is mechanically vconnected-to a lpiston 44 by means oi'fa rod r45.rllhe piston'441is mounted in a cylinder 46to which airisadmittedth-rough an opening 47, which is pneumatically connected with asource vo-f;a. ir under pressure.

An electromagnet 48 controls an arma-ture Y member and valve (notshown)which regulates the supply of air 4that is admitted to the cylinder 46,in accordance with a familiar construction.

A spring 49 normally maintains the :pis

Aton 44 in its lower position, vthereby forcing the arm 38 downwardandcausing the shutter 36 to assume its open position.

In Fig. V3, the shutters 3 6 are .shown in their closed position, and inFigs. 4 and 5,

`the shutters, 36 are shown 1in their open position.

ln Figs. 4 and 5, the lmanner of spacing the ends 43 of the rods '38 issho-wn. For the sake of economyin space, it is necessary that the bentend portion 4 3 of every other rod 38 be arranged at one level and end,portions 43 of the intervening rods 38 be arranged at a higher lever toprovide room for the cylinders 46 and armatures 48.

vrMethods of gradually introducing electrolyte into a Vrheostat toprevent waves are known Vto the art and will not be described in detail.This desirable feature is embodied in my rheostat. When the mastercontroller-(not shown) is actua-ted so .-ass'to :energize one of thevvelectromagnets 48, Vit will permit air to enter the cylinder 46,Lthereby Vraising the piston 44 and the arm 38, causing a shutter toclose. This action will canse the electrolyte to rise and shunt aportio-n of the electrodes 1.8. Any excess electrolyte will flow over4the highest :of the closed lshutters 36, and will then flow, between.the fwalll formed by `the shutters 36 and the outer wall 51, v.downthrough an opening l52 4into the electrolyte reservoir 6, from whence itwill be circulated by the pump 10. The electrolyte is continuouslycirculating to lower the temperature o-t'fthat portion of theelectrolyte which surrounds the electrodes. Y

In Fig. 3 iis shown the 4method of preventing loss `of electrolyte fromthe rheostat 5 by reason otleakage. The inner wall 5,1a is separated`from the outer wall 51 by an airspace 5,3. The .inner wall 51a vis madeas tight fitting ,as possible but if there Vis any .leakage theAelectrolyte tdrains down through the space 53and through an opening 54.into the electrolyte lreservoir 6.

'llhelshapes and positions oi the soapstone barriers 19,which are shownbetween the electrodes 18and 26 in Figs. 2 and 3, may be `betterunderstood by lreferring to Figs. 6, 7, 8 and 9. The barriers 19 arecut-and positioned to form an opening that somewhat :resembles theletter V. However, the barriers 1 9 are not in Acontact with oneanother,as .they are placed instaggered relation. As the electrolyte rises inthe rheostat, the rdistance between the legs of the V being greater, thepath between the main electrodes 18 becomes more direct.

rlhe sloped portions 55 and 56 of veach barrier 19 yare so shaped as toform a sharp edge, whichprevents eddies of the electrolyte. Each of' theground electrodes has a relatively large notch 26aL which is linsubstantial alinement with the openings formed bythe soapstone barriers19. The ypurpose of this notch will be hereinafter described. ln Figs.10 and 11 an auxiliary electrode 21 comprises two plates which arewelded together near their one edge 57 or .they may be bolted togetheras desired. :Theopposite end of the plates 21 are then bent outwardly toform across section resembling the Yletter V. u

Referring again to F ig. 2 and yto Fig. v3, it is apparent that when theelectrolytein the tank is below the ground electrodes 26, the mainVelectrodes 18 ,are electrically conf nected to each other .by a paththrough the electrolyte and the two'outer electrodes 1-8 are connectedto each other by a -path delta connection between the main electrodes 18is maintained but it carries relatively less current by comparison withthe star connection.

vThe purpose of the notch or opening 26 in the ground plates 26 is toavoid having the ground plates 26 directly in that part of the pathbetween the main electrodes 18, that carries the heaviest current, whenthe lr`electrodes 18 are connected only in delta.

Those portions of the ground electrodes 26 that are surrounded first bythe electrolyte are relatively remote from the direct path of current.This path is determined by the soapstone barriers 19, as has alreadybeen described.

When the electrolyte rises until it immerses a portion of the auxiliaryelectrodes 21 an additional path of current is provided to the groundplates 26 and end plates 27.

It is apparent to those skilled in the art that apparatus constructed inaccordance with my invention will be relatively simple in constructionand reliable in operation, and that a more gradual change of resistancein a circuit may be effected with it than has been done heretofore withliquid rheostats that were employed for similar operations.

Vhile I have shown my invention in a preferred form, it is apparent thatminor modiiications may be made in the arrangement of apparatus withoutdeparting 'from the spirit thereof. I desire, therefore, to be limitedonly by the scope of the appended claims.

, I claim as my invention:

1. The combination with a liquid container, of means for causing theliquid to enter said container and a weir comprising a plurality ofshutters individually operable to control the depth of said liquid insaid container.

2. The combination with a liquid container, of means for causing theliquid to enter said container, a plurality of horizontal shutters andmeans for operating the respective shutters to regulate the depth ofsaid liquid in said container.

3. The combination with a liquid container, having one side normallyopen, and means for circulating a liquid therethrough,

of means for gradually building up said side to increase the liquidlevel.

4. The combination with a liquid Container, having one side normallyopen, and means for circulating a liquid therethrough, of a plurality ofmembers adapted to be arranged in vertical relation to any predeterminedheight to fix the liquid level.

The combination with an electrolyte container, a plurality of electrodespositioned in said container, means for forcing the electrolyte intosaid container, a plurality of shutters, and means for operating therespective shutters to vary thedepth of liquid in said container.

6. The combination with a liquid rheostat comprising` a plurality ofvertical barriers movably mounted, means for maintaining said barriersin their open positions, and means for closing` said barriers to operatesaid rheostat.

7. The combination with a liquid-containing tank and a plurality ofplates adapted to be positioned in said tank, of a plurality ofpivotally mounted barriers, and means for operating the respectivebarriers to vary the depth of said liquid in said tank.

8. The combination with. an electrolyte container, of a plurality ofplates positioned in said container, means for forcing electrolyte in-said container, a movably mounted barrier for varying the height ofsaid electrolyte in said container, an arm for operating said barrier,resilient means for maintaining said arm in one position, and meanscomprising an electromagnet for operating said arm to another position.

9. The combination with an electrolyte container, of a plurality ofelectrodes mounted in said container, a plurality 'of 105 barriers forvarying the height of said electrolyte, said barriers being pivotallymounted and their corresponding surfaces adapted to form a plane uponbeing actuated to their closed positions, resilient means formaintaining said barriers in their open positions, means Comprising aplurality .of pistons operated by air pressure for actuating saidbarriers, a plurality of electromagnets for controlling the air uponsaid pistons, and means for controlling the energization of saidelectromagnets.

10. In a liquid rheostat, the combination with a plurality ofelectrodes, of an insulating barrier between them to increase the'distance traversed by current through the liquid 'between saidelectrodes, said barrier heilig so shaped that upon said liquid beingincreased in dept-h, a shorter path between 195 said electrodes isprovided.

11. In a liquid rheostat, the combination with a plurality ofelectrodes, of a plurality of insulating barriers between saidelectrodes, said barriers being so shaped that the distance traversed bycurrent through electrmleevr ilcreaees.

A12. rIhe combination with an electrolytecontaining tank, and aplurality lof .elC-

trodes positioned in said tank,l .of means for ynry-ing` the` depth ,ofsaid, electrolyte in said tank7V and a plurality of barriers instaggered. relation to; each other and s0 shaped that4 the Winding pathof a currentV between Said electrodes is gradually straightened upon agradual increase inv depth of said electrolyte.V l

13. In a liquid rheostat, the combination with -a plurality ofelectrodes, .of meansor gradually inserting af difierent type .ofelectrical connection between said'V electrodes. Vupon varying the depth.of the liquid.

14, In a liquid rheostat, the combination. with a plurality of.electrodes,r of means coinprising an electrolyte, to. gradually Sllllntthe electrodes andv to. foi-ina. different type of connectiontherebetween.

Vl5. In a liquid rheostat, the 4conobination with a plurality of Vnnainelectrode@ and anl electrolyte for connecting them in delta and forgradually shnntngfsaid electrodes., of a plurality of ground electrodes,electrically "connected 'tof each Vother and so posi.- ftioned inrelationv to said noanfl .electrodes that a star connootion between saidV main electrodes through said electrolyte isV foi-ined in addition tof``'said delta cdnnection by yalyng the quantity of electrolyte,surrounding Said .main and ground electrodes. 16. An 'electrode for aliquid rheostat comprising an integral body .of snbSlelltially Y-SbopefAn electrode `for a. liquid rheostat comprising sheets ofrnaterialsecured relatively Vo los'e together .at one end thereof andseparated sornefdistanoe apart at their'other In a liquid rheostat, thecomb i] lationl Y .with a" tank, fof means for ycirculating the liquidthrong-h Said tank, a plurality of main electrodes in 'Sid'e-luf-Sfle.relation in said tank;sad..` electrodes being of. Substan- .tiallyY-ehape with two .ofthe legs, .Of each electrode sov bent as. to beparallel to. the

Y third leg thereof, an auxiliary .electrode po..-

eitionedyythin eael'il ofthe, main. electrodes, a plurality of groundelectrodes in Sideby-side relation to said main electrodes and connectedto. each other-and to said aufrilialy 'elect-rodeo, said moinelootrodesbeillg connected toV each other upon the liquid reaching acertain level in said tanl; and

` upon reaching a .higher level Said main noemen@ .being .so shaped thatthe. portion .thereof 21. lille Celllbnatonnnh o pluralityv oi"V .mainelectrodes, of a pluralityof barriersbetween said electrodes,` saidbarriers being shapedand positionedv to form a groove through whichcurrent between. vSaid Ina-n eletr'odes must. circulatelnlld an,additional electrode hailing .a grooveuluoh ie in alinenoent. wth'the"grooye drned by Said barrlers- In liquidrheostat. of the-p olyphasetype, the combination with. @plurality of electrodes, off means forforming V@.lle'relrlt types .0f Plypllose connections, of said elec.-

trodes..inaccordanoo with thedeptb of the liquid'.-

23. In a liquid rheoetat of the threepbase type, .thefoornbnaton withplurality of ,e.leotrod'es,l of .means oolnprongon eleotrolyte adaptedto gradually-Shunt'ead .eleotrodeo and change thefoonneoton thereoffrein Ydelta to combined delta ,and Stal- 214... In 'a liquid rheostatof the threepl-ias'e. type, the' Combination with@ plurality of.eleotrodes, of meansffor .forming first a. delta and .then a starconnection `of Said electrodeeaccordance with the depth of ne .1i-quid.1 n

25.' In a liquid rheostat, the coinbinatio with a plurality ofelectrodes, and an eleo- .trolyte for connecting tben in .delta and .forgradually ehunting Said-electrodes, of a slecond set of electrodes sodisposed in relation 4to the tiret-named elect-redes that a' Staroonneotion between the two sete .of eleotrodee isV also formed upon a.predetermined increase in the level of said electrolyte.

2.6.' In a liquid rheoetat, the combination with a -netal container,Vand' a plurality of main electrodes normally `irlonl'otetl there-Yfxionu and from each other, of lan auxiliary. Velectrode connected to.said container, and

of shorter length than said main electrodes.

Ano

27. In a liquid rheostat, thecombination .With a container of conductingmaterial,` of av plurality `of electrodes arranged in a row andinsulated' from tbe'oontoner and. from each other7 and a plurality ofadditional electrodes connectedto said container and respectiyelylocated between adjacent. pairs of they first named eleotrodee nl hunmet ne combinacion with a container of conducting material, ofelectrodes being of shorter length than the a plurality of electrodesarranged in a row other` electrodes.

and insulated from the container and from In testimony whereof, I havehereunto 10 each other, and a plurality of additional subscribed mynaine this 13th day of Octoelectrodes connected to said container andber,1920.

respectively located between adjacent pairs of the first namedelectrodes, said additional CHARLES C. YVHITTAKER.

